In a medium saucepan, over medium-high heat, add sugar and water. Heat until sugar melts, stirring regularly. Allow the mixture to come to a boil for 3 minutes and DO NOT stir. Then add a squeeze of fresh lemon juice or about 1 teaspoon. Then boil another 3 minutes. Let it cool completely.  

Remove kanafeh from package. Take about a (3/4"/ 2cm) thick strand of kanafeh and re-wrap the rest or cover with damp paper towel to prevent from drying out.

Roll the kanafeh strand around the cone form. Start by placing one end of the strand in the middle of the cone, then beginning from the tiny, closed end of the form, tightly wrap the remaining strand over the end and overlapping that middle piece and up until you almost reach the wide opening of the form. Leave a small piece of the metal form showing; this will later make it easier to grab onto while removing the baked cones. Make sure that the kanafeh is wrapped as tightly as possible without tearing, and that there are no gaps showing. To make the kanafeh stick to itself and prevent unrolling, dampen your hands with a little bit of water, then use them to apply pressure on the wrapped kanafeh, pressing tightly on it until its stable and all the stray strands are stuck. Don't get it too wet; just damp enough to stick the kanafeh to itself. Repeat with the remaining kanafeh.

Place the wrapped kanafeh cones on a baking sheet, cover loosely with a sheet of foil or parchment paper and leave to air dry until the kanafeh feel hard to the touch; 3 hours to overnight.

When ready to bake, adjust oven rack to middle position and preheat the oven 200C/ 400F.

IMPORTANT: Loosen the hardened kanafeh from the metal form so its not so stuck to it anymore, but do not remove completely. This will make it easier to later remove the kanafeh from the form without breaking. If you don't do that, you'll have a very hard time removing the baked kanafeh from the form.

Pour the melted ghee (or butter) into a shallow bowl. Dip and roll the kanafeh cones into the ghee to saturate. Allow excess ghee to drip back into the bowl.

Place the ghee dipped kanafeh cones on their sides onto a baking sheet. Bake the cones, rotating them every 5 minutes on a different side to ensure even browning until the kanafeh is all golden brown in color, 15 to 20 minutes.

Remove from the oven, then immediately transfer the cones to a clean pan. Drizzle the piping hot kanafeh with the cooled syrup. Move the kanafeh around to coat with the syrup.

Then place the cones standing upside down to cool completely and allow to drip all the excess syrup and ghee.

Once cooled, carefully twist the cones to remove from the form. If you're having a hard time removing it, place in the freezer to cool further then try again.  

In a bowl, stir together mascarpone and tahini until fully combined. Then add the powdered sugar in a little bit at a time. 

Fill a pastry bag or ziplock bag with tahini mascarpone. Hold the kanafeh cone upright in one hand and squeeze the filling into the cone with the other until you have the desired amount. Top with pistachios.